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Unable To Run Two Microsoft Loopback Adapters At The Same Time RRS feed

  • Question

  • Hi

    I have one Visual Basic sender application which sends data to two Visual Basic receiver applications via two different loopback adapters (of different IP addresses) on the same computer:

     1) VB application 1 uses loopback adapter #1

     2) VB application 2 uses loopback adapter #2

    When I run one receiver application at a time at such:

     1) VB Sender application and VB receiver application 1

     2) VB Sender application and VB receiver application 2,

      the data is acquired successfully from the sender program, however when I run two receiver programs concurrently at such:

     1) VB Sender application and VB receiver application 1 & 2,

    only receiver application 1 managed to retrieve data from the sender application, while receiver application 2 retrieves no data until I close receiver application 1.

    I am able to retrieve data for both receiver applications on Windows XP but not Windows 7. I am wondering if there is any setting which I have missed out in order to run two loopback adapters at the same time? Is it possible to run two loopback adapters concurrently?

    Thanks!



    • Edited by holytree Thursday, July 2, 2015 7:57 AM
    Thursday, July 2, 2015 7:50 AM

Answers

  • Hi Deason

    Thank You for your help. I have installed Windows XP Mode in Windows 7 and the problem persists. I have managed to keep my loopbacks running concurrently on Windows 7 by using the mswinsck.ocx file from my Windows XP computer which is a different version from what I have in Win 7 and everything is working fine now :).

    Regards

    holytree

    • Marked as answer by Deason Wu Tuesday, July 21, 2015 12:52 AM
    Monday, July 20, 2015 9:26 AM

All replies

  • Hi,

    I never thought/tried 2 loopback adapter could work together, since you mentioned that it worked in Windows XP, I guess it could be. I wonder if two IP addresses are on the same subnet. It is possibly that when you send to these IPs, the network expects that they are on the same interface. So the primary one will get the data. Since as I know loopback interfaces are not routable, I don’t know if we can set up multiple network connections using Microsoft Loopback Adapter, use different subnets. Do not set a value for Default gateway.

    Regards,

    D. Wu


    Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

    Monday, July 6, 2015 2:29 AM
  • Dear D. Wu

    Thank You for your help. I have tried using different subnets for each IP address with no value for Default gateway, unfortunately, the behavior persists. I am wondering if the difference between the XP (ver. 5.1.2600.0)and Win7's (ver. 6.1.7600.16385) driver (loop.sys) is causing this phenomenon as I realised that under the loopback adapter's advanced configuration of XP, there is this property field 'Medium' and value 'Ethernet' and no such field in Win7's.

    Regards

    holytree

    Tuesday, July 7, 2015 1:44 AM
  • Hi,

    They must be changed, the Windows 7 version on my test machine is 6.1.7600.16385. Since you mentioned that Windows XP works under same configuration. Under normal circumstances we could try that under XP mode, but consider that you are using it for program test I guess it is not quite meaningful.

    Install and use Windows XP Mode in Windows 7

    http://windows.microsoft.com/en-us/windows7/install-and-use-windows-xp-mode-in-windows-7

    Regards,

    D. Wu


    Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

    Friday, July 10, 2015 6:11 AM
  • Hi Deason

    Thank You for your help. I have installed Windows XP Mode in Windows 7 and the problem persists. I have managed to keep my loopbacks running concurrently on Windows 7 by using the mswinsck.ocx file from my Windows XP computer which is a different version from what I have in Win 7 and everything is working fine now :).

    Regards

    holytree

    • Marked as answer by Deason Wu Tuesday, July 21, 2015 12:52 AM
    Monday, July 20, 2015 9:26 AM
  • Hi,

    Glad to hear this issue has been solved. Thanks for sharing. We really appreciate
    your time and efforts. Hope your experience will help other community members
    facing similar problems.

    Regards,

    D. Wu


    Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.


    • Edited by Deason Wu Tuesday, July 21, 2015 12:52 AM
    Tuesday, July 21, 2015 12:52 AM